KINGDOM: Animalia | PHYLUM: Arthropoda | CLASS: Insecta | ORDER: Hemiptera | FAMILY: Coreidae (leaf-footed bugs) & Rhopalidae (scentless plant bugs)

Leaf-footed Bugs (Family Coreidae) & Scentless Plant Bugs (Family Rhopalidae) are two similar insect families in the in the order Hemiptera (which also includes assassin bugs, stink bugs, and other insects).  All insects in Hemiptera share a few characteristics, including piercing-and-sucking mouthparts, and wings (called hemielytra) which are membranous at the tips but hardened at the base.

Leaf-footed bugs can be difficult to distinguish from other Hemiptera, especially assassin bugs, which are often similar in size (3/4" - 1").  In many leaf-footed bug species, the back legs are wide and leaf-like in shape, but this is not true for all species, including some common varieties like the squash bug.  Often, the only way to determine the identity of a leaf-footed bug is with a microscope: leaf-footed bugs have 4-segmented beaks, assassin bugs have 3-segmented beaks.

Scentless plant bugs are similar to leaf-footed bugs.  In fact, some scientists and field guides place scentless plant bugs in the leaf-footed bug family.  But scentless plant bugs are usually much smaller: rhopalids found in Kentucky are less than 1/2" long.

Like all Hemiptera, leaf-footed bugs and scentless plant bugs go through a simple metamorphosis with egg, nymph, and adult stages.  Females of most species lay eggs during warm months.  The eggs are often stuck to leaves or branches, or hidden under bark, depending on the species.  After hatching, the wingless nymphs molt several times before becoming full-sized, winged adults.  The adults will often mate and reproduce numerous times during the growing season.  Large nymphs or adults are usually the overwintering stage.

There are several species of leaf-footed bugs and scentless plant bugs in Kentucky.  They are all believed to be herbivores: they use their piercing-and-sucking mouthparts to feed on plant juices.  Many are able to feed on a variety of plants, including crop and garden species.  (A few sources, including field guides and and websites, mention that some leaf-footed bugs are predatory, but modern experts believe that this is probably not true).

Like stink bugs, leaf-footed bugs are able to secrete foul-smelling, foul-tasting fluids from pores on the sides of their bodies.  These secretions help to protect leaf-footed bugs from predators.  Nevertheless, leaf-footed bugs are often eaten by birds, spiders, assassin bugs, and other predators.  Scentless plant bugs, as their name suggests, do not have scent glands.

Although several species of leaf-footed bugs can be pests, Kentucky has only one important leaf-footed bug pest, the Squash Bug, Anasa tristis.  The only pest scentless plant bug in Kentucky is the Boxelder Bug.  Both of these insects are discussed in detail below.

SQUASH BUG
GENUS and SPECIES: Anasa tristis
The Squash Bug, Anasa tristis, feeds on squash, cucumbers, and related plant species.  It can be found throughout the growing season on these plants.  The eggs of the squash bug are pictured above.  Squash bugs are about 17 mm when full grown.

HORNED SQUASH BUG
GENUS and SPECIES: Anasa armigera
Pictured below is Anasa armigera, the Horned Squash Bug.  This leaf-footed bug resembles the squash bug in both behavior and appearance, and is sometimes a pest of pumpkins and similar vegetables.  It is encountered less frequently than the common squash bug, and differs in having two small "horns" at the base of each antennae.

Read more about pest boxelder bugs in our Boxelder Bug ENTFact.

Leaf-footed bugs are fairly common, and can be found on summer and fall days in gardens, crops, weeds, trees, and other vegetation.  In particular, squash bugs are very commonly found underneath the leaves of squash plants and related garden plants.

Some leaf-footed bugs have unique appearances, and make nice photo subjects or additions to an insect collection.  Like many Hemiptera, leaf-footed bugs and scentless plant bugs are normally slow moving and do not fly very often, so they are easy to capture and photograph.

Other than boxelder bugs, which are often very common, scentless plant bugs are not as common as leaf-footed bugs.  Sampling tall weeds with a sweep net will occasionally yield members of this family.

Some leaf-footed bugs have very unusual back legs.  Here is a striking example from Paraguay on the "God of Insects" site.

Do you know any myths, legends, or folklore about leaf-footed or scentless plant bugs?  Let us know if you do!